INCREASED FIBER HYDROLYSIS BY PROTEASE ADDITION

• US 20090098638A1
• Filed: 10/08/2008
• Published: 04/16/2009
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: Charles A. Abbas, Wu-Li Bao
• Original Assignee: Charles A. Abbas, Wu-Li Bao
• Inventors: Bao, Wu-Li, Abbas, Charles A.
• Granted Patent: US 8,815,571 B2
• Time in Patent Office: Days
• US Class Current: 435/276
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• CPC Class Codes: C12P 19/20 produced by the action of an exo-1,4 alpha-glucosidase, e.g. dextrose
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

Novel fiber processing methods and the products obtained therefrom are disclosed. Methods may include thermochemical and/or enzymatic hydrolysis of fiber feedstocks including distillers'"'"' dried grains, distillers'"'"' dried grains with solubles, soyhull, miscanthus and switchgrass. Enzymatic hydrolysis includes hydrolysis with cellulase, hemicellulase, and protease.

Claims

1. A method for increasing the amount of glucose and other sugar and peptides released from a fiber feedstock comprising:

(a) reacting a fiber feedstock with a mixture of reactants comprising at least one protease and at least one member of the group consisting of cellulase and hemicellulase; and

(b) obtaining a reaction product from said fiber feedstock and said mixture of reactants comprising glucose, wherein the amount of glucose in the reaction product (measured as a percentage of the fiber feedstock mass) is greater than the amount of glucose obtained from reaction of the fiber feedstock under the same conditions as the reaction of step (a), but with at least one member selected from the group consisting of cellulase and hemicellulase and excluding protease.

2. The method of claim 1, wherein said mixture does not include amylase.

3. The method of claim 1, wherein said protease is an acid fungal protease.

4. The method of claim 1, wherein said protease has an amino acid sequence at least 95% identical to the amino acid sequence of SEQ ID NO:

1.

5. The method of claim 1, wherein said protease is selected from the group consisting of Aspergillus saitoi aspartic protease, Penicillium acid protease, Mucor acid protease, Monascus acid protease, Trichodenna acid protease, Phaeosphaeria acid protease, and Rhizopus acid protease.

6. The method of claim 4, wherein said protease is Aspergillus saitoi aspartic protease, said Aspergillus saitoi aspartic protease having the amino acid sequence of SEQ ID NO:

1.

7. The method of claim 1, wherein said fiber feedstock is selected from the group consisting of corn stover, corn gluten feed (CGF), distillers'"'"' dried grains (DDG), distillers'"'"' dried grains with solubles (DDGS), switchgrass, soyhulls, wheat chaff, and wheat straw.

8. The method of claim 1, wherein said fiber feedstock comprises less than 20% starch by weight.

9. The method of claim 1, wherein said fiber feedstock comprises less than 10% starch by weight.

10. The method of claim 1, wherein said fiber feedstock comprises less than 5% starch by weight.

11. The method of claim 1, wherein said fiber feedstock comprises 0% starch by weight.

12. The method of claim 1, wherein said mixture of reactants comprises cellulase, and wherein said cellulase comprises one or more of endo-β

-1,4 glucanases, exo-cellobiohydrolases, β

-glucosidase (cellobiase), and exoglucanases.

13. The method of claim 1, wherein said mixture of reactants comprises hemicellulase, and wherein said hemicellulase comprises one or more of endo-1,4-β

-xylanase, β

-xylosidase, β

-endomannanase, β

-mannosidase, pectin lyase, pectate lyase, α

-L-arabbinofuransidase, α

-glucuronidases, α

/β

-galactosidases and several esterases.

14. The method of claim 1, wherein said reaction product further comprises arabinose, xylose, galactose, mannose, cellulobiose, maltose, and maltotriose.

15. The method of claim 1, wherein the amount of glucose in the reaction product (measured as a percentage of the fiber feedstock mass) is greater than the amount of glucose obtained from reaction of the fiber feedstock by at least 100%.

16. The method of claim 15, wherein the amount of glucose in the reaction product (measured as a percentage of the fiber feedstock mass) is greater than the amount of glucose obtained from reaction of the fiber feedstock by at least 20%.

17. The method of claim 16, wherein the amount of glucose in the reaction product (measured as a percentage of the fiber feedstock mass) is greater than the amount of glucose obtained from reaction of the fiber feedstock by at least 10%.

18. The method of claim 1, wherein said protease has an amino acid sequence selected from the group consisting of SEQ ID NO:

1, SEQ ID NO;

2, SEQ ID NO;

3, SEQ ID NO;

4, SEQ ID NO;

5, SEQ ID NO;

6, SEQ ID NO;

7, SEQ ID NO;

8, SEQ ID NO;

9, SEQ ID NO;

10, SEQ ID NO;

11, and SEQ ID NO;

12.

19. A method for obtaining a solid hydrolyzed fiber for production of biooil, comprising:

(a) preparing a reaction product according to claim 1; and

(b) separating said reaction product into a solid hydrolyzed fiber fraction and a liquid fraction.